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The reproductive biology of P lagioscion squamosissimus ( H eckel, 1840) in the P ará R iver estuary ( A mazon E stuary)
Author(s) -
Barbosa N. D.,
Rocha R. M.,
Lucena Frédou F.
Publication year - 2012
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/j.1439-0426.2012.02040.x
Subject(s) - biology , estuary , reproductive biology , amazon rainforest , zoology , fishery , ecology , embryo , embryogenesis
Summary This study describes the reproductive biology of the S outh A merican silver croaker P lagioscion squamosissimus ( H eckel, 1840) in the P ará R iver estuary. Data were collected bimonthly from J une 2007 to M ay 2008. In all, 334 specimens were examined. The gonads were processed with histological techniques, and the ovaries were subjected to morphometric analysis. The length at first maturity (L 50 ) values were 16.14 and 21.43 cm total length for females and males, respectively. The sex ratio based on the total number of individuals favoured the females (1.11 females: one male). Macroscopically, the gonads were classified as immature ( A ), maturing ( B ), mature ( C ) and spent ( D ). Microscopically, four germ cell types were distinguished based on the development of the ovaries. Chromatin nucleolus ( I ), perinucleolar ( II ), cortical alveoli ( III ) and full‐vitellogenic ( IV ) oocytes were observed in all ovarian stages, except that of the mature individuals which showed the largest number of full‐vitellogenic oocytes ( IV ), with a mean diameter of 565.4 μ m (±147.4). Substantial percentages of individual P . squamosissimus were found to be in a reproductive condition. Reproductive activity was recorded throughout the year in the Pará River estuary, primarily in F ebruary/ M arch and A ugust/ S eptember.